RK-2001UA Controlling a Laddomat

[Tennman]

I'm planning on using the pump power plug from the BioMass to control the Laddomat 21-100. The Laddomat manual talks about using a flue temp switch, but I think the pump launch temp and pump hysteresis (P144 and P4) could control the loading unit. Prior to storage these parameters controlled the boiler to HX circ pump. If I'm right about P144 launch and P4 pump-off controlling the Laddo, what values do you use?

Once again, stepping into the unknown with Hearth as my lifeline. Thanks

 

[Mike Fromme]

I use the RK2000 controller to turn on and off my storage pump... Set to the highest pump launch (170 I think) and the smallest hysteresis (4 I think).

It works but the downside is the pump runs for a long time after the fire is out. Resulting in more standby losses.

A flue temp sensor would turn the pump on and off when there is fire or not. Less standby loss.

 

[BoiledOver]

For the first year with an Eko, I used the RK to launch the storage circuit just as Mike stated above. It worked well enough with just an esbe valve and will probably be ok for your loading unit too. Storage sure is nice stuff hey, congrats on that.

 

[Tennman]

Thanks guys. Yeah, I can see how it would take a while for the boiler water temp to fall off. I really don't care so much about the electricity cost as much as losing stored energy. Once I get it running I'll watch the water output temp. If it stays above 180F then I can increase the launch temp and reduce hysteresis to reduce the pump off delay.

BoiledOver, so how do you launch now?

This season I'll use the RK because it's there and works. I expect there will be plenty of other things to debug. Yeah, pretty jazzed after 5 years... storage! Thanks!

 

[BoiledOver]

BoiledOver, so how do you launch now?

Pump launch using an On/Off/On switch. At fire startup the switch is at the always on position. After 20 minutes or so when things are warm, the switch goes to the other on position which feeds through a Johnson A419 aquastat. The aquastat is good for unattended endings, set it high and no worries. The diff can be as small as 1 degree with these units.

I still use the RK for part of the blower control and for boiler temp. The RK blower parameters could not go low enough to suite me, the dang thing on low would have flue temps right around 500 F and sometimes higher. I now have a variable fan speed controller in line after the RK. At beginning the RK is set to 100 and variable controller all the way up. Once the flue temp reaches 300-350 F, I reduce the RK to 70 and the variable controller works well at about 50%. That is pretty slow but any slower and the gases will ignite in the upper chamber (makes for a lil backfire). The net result is a nice 390-430 F flue temp.

 

[Tennman]

Wow.... pretty clever Boiled. I was born electrically handicapped so I won't be adding much in the way of controls. But it sounds like you improved incrementally. That may be something down the road I will play with once I get a working baseline. Sounds like you have that EKO humming. congrats.

 

[Bob Rohr]

I switched to a solar (delta T) controller to start the boiler pump. The boiler feeds to an 80 gallon buffer. So when the delta t between boiler and tank is degrees 12 pump starts, runs until the delta drops to 6. Then I put a min start temperature of 130 on the boiler sensor.

This solar controller could also vary the speed of the boiler pump, revving up as temperature increases. Not quite a 100% boiler protection, however, but a simple control to allow a lot of adjustability. Plus some data logging for hours run time and BTU estimates, with a 3rd sensor on return and flow rate estimation programed in.

 

[Tennman]

Bob, Are you using a pump or loading unit? You have storage correct? If so then the buffer's between the boiler and storage? Not sure if my Laddo pump motor can handle variable speed. Anyway, pretty cool control solution. I'm definitely your meat and potatoes kind of guy for control matters.